In the initial 2 groups of normal monkeys peridically repeated in vivo studies will be performed. These studies include blood tests, EKG by radiotelemetry and under anesthesia, echocardiography, determinations of the left ventricular end-diastolic pressure, coronary and peripheral arteriography, ventriculography, peripheral circulation studies, atrial pacing, stress exercise and ocular fundus studies. These animals will be sacrificed at the end of year 3 (present application) and biochemical and morphological studies will be performed on coronary, peripheral and other arteries as well as of heart, eyes and other organs. Other adult male Macaca fasicularis monkeys have been purchased in the current year and were divided into 3 groups. The first group will be exercise conditioned and then placed on an atherogenic diet while continuing conditioning exercise. The other 2 groups were placed on an atherogenic diet. One of these groups is scheduled to continue this diet for 36 months with limited physical activity; while the other group is scheduled to consume this diet for 18 months and then begin moderate treadmill exercise will continuing this diet. All new animals have been trained to operate the Primate Activity Wheel to prepare them for the periodic stress exercise tests scheduled for the coming year. In addition, the same baseline studies have been performed in the new monkeys as in the initial colony. Pertinent studies will be repeated at appropriate intervals, especially EKG's by radiotelemetry at rest and under regular and stress exercise, echocardiography, coronary and peripheral arteriography and peripheral circulation studies.